The same new moon that sets up the total solar
eclipse Aug. 1 will create dark night-sky conditions for stargazing, making
this a great time to check out the beautiful midsummer Milky Way.
Campers and rural residents should have little
trouble spotting it, weather permitting.
As soon as darkness falls, the Milky Way becomes
evident as a wide glowing arch of variety and beauty, stretching high across
the sky from the northeast to southwest.
Sweep with binoculars up from the tail of the
constellation Scorpius, low in the southwest through the Summer Triangle,
almost overhead and down toward Cassiopeia and Perseus in the northeast. You'll
find concentrations of stars, clusters, large apparent gaps such as the Great
Rift in Cygnus, and more stars than you thought existed.
Never visible from large cities with their bright lights,
smoke and haze, the Milky Way can
still be readily viewed from distant suburbs and rural locations. Visually it
appears as a faint, albeit distinct ghostly band of light; it almost looks more
"smoky" than "milky" in appearance. From a truly dark site,
however, it appears in full glory: The brightest portions can cast faint
shadows, and it appears highly complex and structured
to the unaided eye and like veined marble when viewed with ordinary binoculars.
What it is
Before the invention of the telescope, the true nature of
the Milky Way Galaxy ("Gala" is Greek for milk) was a mystery. Now we
know it's a concentration of stars in our own galaxy.
The galaxy's center is about 26,000 light-years away toward
the Sagittarius star cloud. From where we sit, the galaxy's outer edge is about
20,000 light-years in the opposite direction (toward Auriga and Taurus). We reside
on a spur of the Orion arm, and what we see as we look at the Milky Way in our
night sky is just a portion of nearest stars between us and the galactic center.
The sun and all the outer stars of the galaxy revolve around
the galactic
center at the rate of 155 miles per second. It apparently requires about
225 million of our earthly years to make one complete revolution, or one "cosmic
year," around the center of our galaxy.
When we began to realize that there were other such
vast collections or aggregation of stars, we called them "island
universes," but this was an obvious misnomer; since universe means
everything there is, it can hardly have a plural. So we've seemed to have
settled on "galaxies," which is a compromise as a new meaning for an old word.
What was that eerie cloud?
Unfortunately, because of the tremendous increase in light
pollution over the past quarter century, the majority of our current generation
have never seen the night sky in all
its grandeur.
In his book "Nightwatch," the well-known Canadian
astronomer Terrence Dickinson comments that in the aftermath of the predawn
1994 Northridge, California earthquake, electrical power was knocked out over a
wide area. Tens of thousands of people in southern California rushed out of
their homes looked up and perhaps for the first time in their lives saw a dark,
starry sky. In the days and weeks that followed, radio stations and
observatories in the Los Angeles area received countless numbers of phone calls
from concerned people who wondered whether the sudden brightening of the stars
and the appearance of an eerie silvery cloud (the Milky Way) might have caused
the quake.
"Such reaction," notes Dickinson, "can come
only from people who have never seen the night sky away from city lights."